Antibiotics paulomycin A and paulomycin B are disclosed in U.S. Pat. No. 4,335,108. These antibiotics are produced in a fermentation using Streptomyces paulus, strain 273,NRRL12251. Example 1 of U.S. Pat. No. 4,335,108 discloses the fermentation process and recovery of the desired antibiotics. Examples 2 and 3 disclose the isolation processes for preparing the essentially pure crystalline preparations of paulomycin A and paulomycin B, respectively.